1. Field of the Invention
The invention relates to an arrangement for electrically conductively connecting two electrical units by means of a bipolar high voltage direct current transmission in which at least two electrical direct current cables are arranged between the units.
“Electrical unit” in the sense of the invention may be, for example, a current supply network, a power station, a transforming station, a resetting station, as well as also sections within such units. In the following, representative for all possibilities of application, the word “network” is used instead of the words “electrical unit.”
2. Description of Related Art
In today's technology, such arrangements are used in so-called energy networks in order to realize a two-point connection with a high transmission power, as it is necessary, when a power station is connected to a network. Using such an arrangement, it is also possible to connect different networks to each other by means of bipolar high voltage direct current transmission. This is basically true for all networks existing on Earth which as three-phase current networks can also offer different frequencies. The networks can also be connected to each other over longer distances. The direct current cables used in the known technology are prone to losses. In this connection, on the one hand, the level of the losses of the direct current cable increases linearly with the distance between the respective networks and, on the other hand, relative to the square of the power being transmitted. Therefore, it must be ensured that an electrically conducting cross-section sufficient for all cases is available using the appropriate efforts. This can be achieved with conventional technology by a parallel displacement of an appropriate number of direct current cables.